Sign in to Visual Studio 2013 within 14 days with your Microsoft account to synchronize your settings across multiple machines and register your product.
NOTE: For Visual Studio 2013 Preview, this experience is only available in English.
Here are the screenshots for the experience
If you have two-factor authentication enabled use the Authenticator App and enter your code
Choose your settings and theme
If you want to view your profile click the hyperlink and you will be brought to a web page where you can review your contact information
Now all your settings can be synchronized!
You are also able to access your profile within Visual Studio 2013